Objective To investigate whether screening for thyroid cancer led to the current “epidemic” in South Korea. Design Review of the medical records of nationally representative samples of patients with a diagnosis of thyroid cancer in 1999, 2005, and 2008. Setting Sample cases were randomly selected from South Korea’s nationwide cancer registry, using a systematic sampling method after stratification by region. Participants 5796 patients with thyroid cancer were included (891 in 1999, 2355 in 2005, and 2550 in 2008). Main outcome measures The primary outcome was age standardised incidence of thyroid cancer and the changes in incidence between 1999 and 2008 according to the methods used to detect tumours (screen detection versus clinical detection versus unspecified). Results Between 1999 and 2008, the incidence of thyroid cancer increased 6.4-fold (95% confidence interval 4.9-fold to 8.4-fold), from 6.4 (95% confidence interval 6.2 to 6.6) per 100 000 population to 40.7 (40.2 to 41.2) per 100 000 population. Of the increase, 94.4% (34.4 per 100 000 population) were for tumours less than 20 mm, which were detected mainly by screening. 97.1% of the total increase was localised and regional tumours according to the Surveillance, Epidemiology, and End Results (SEER) summary stage. Where cases were clinically detected, 99.9% of the increased incidences (6.4 per 100 000 population) over the same period were tumours less than 20 mm. Conclusion The current “epidemic” of thyroid cancer in South Korea is due to an increase in the detection of small tumours, most likely as a result of overdetection. Concerted efforts are needed at a national level to reduce unnecessary thyroid ultrasound examinations in the asymptomatic general population.

The divorce rate has been increasing rapidly in Korea; the single rate and trends in divorce are also changing rapidly. This study aimed to examine the relationship between marital status and quality of life (QOL) in an attempt to understand these changes. We also investigated the relationship between QOL and marital status by age group. We used data from the Community Health Survey (2008: n = 200,800; 2009: n = 227,700; 2010: n = 229,229) administered by the Korean Centers for Disease Control and Prevention. After excluding 63,527 participants with incomplete information on QOL and/or marital status, the final analysis involved 594,202 participants. The analysis used t-tests and Chi-square tests to compare demographic variables between men and women, and ANOVA to compare QOL scores among comparison groups. We also performed a multilevel analysis on the relationship between QOL and marital status while accounting for the provincial differences. The multilevel analysis by marital status showed that single men had significantly worse QOL (both EQ-VAS and EQ-5D) than married men. On the other hand, the QOL measured by EQ-VAS was better in single women than in married, and separated or divorced women. When QOL was assessed using EQ-5D, single and separated or divorced women had worse scores than married women. In the analysis by age group, the QOL of married men under the age of 30 years was lower than that of single men or men with marriage problems as measured by EQ-VAS. However, among 40–69-year-old men, married men had the highest QOL values. Similarly, for women in their 30s, single women had the highest EQ-VAS values, but for 40–69-year-old women, single women had lower EQ-VAS scores than married women. There was significant relationship between marital status and QOL, and this relationship appeared to differ by gender and age.

Background: Smoking is by far the most important cause of cancer that can be modified at the individual level. Cancer incidence and mortality rates in Korea are the highest among all Asian countries, and smoking prevalence in Korean men is one of the highest in developed countries. The purpose of the current study was to perform a systematic review and provide an evidence-based assessment of the burden of tobacco smoking-related cancers in the Korean population. Methods: Sex- and cancer-specific population-attributable fractions (PAF) were estimated using the prevalence of ever-smoking and second-hand smoking in 1989 among Korean adults, respectively, and the relative risks were estimated from the meta-analysis of studies performed in the Korean population for ever-smoking and in the Asian population for passive smoking. National cancer incidence data from the Korea Central Cancer Registry and national cancer mortality data from Statistics Korea for the year 2009 were used to estimate the cancer cases and deaths attributable to tobacco smoking. Results: Tobacco smoking was responsible for 20,239 (20.9%) cancer incident cases and 14,377 (32.9%) cancer deaths among adult men and 1,930 (2.1%) cancer incident cases and 1,351 (5.2%) cancer deaths among adult women in 2009 in Korea. In men, 71% of lung cancer deaths, 55%–72% of upper aerodigestive tract (oral cavity, pharynx, esophagus and larynx) cancer deaths, 23% of liver, 32% of stomach, 27% of pancreas, 7% of kidney and 45% of bladder cancer deaths were attributable to tobacco smoking. In women the proportion of ever-smoking-attributable lung cancer was 8.1%, while that attributable to second-hand smoking among non-smoking women was 20.5%. Conclusions: Approximately one in three cancer deaths would be potentially preventable through appropriate control of tobacco smoking in Korean men at the population level and individual level. For Korean women, more lung cancer cases and deaths were attributable to second-hand than ever-smoking. Effective control programs against tobacco smoking should be further developed and implemented in Korea to reduce the smoking-related cancer burden.

The aim of this study was to analyze the clinicopathologic characteristics and prognosis of signet ring cell carcinoma (SRC) according to disease status (early vs advanced gastric cancer) in gastric cancer patients. The prognostic implication of gastric SRC remains a subject of debate. A retrospective analysis was performed using the clinical records of 7667 patients including 1646 SRC patients who underwent radical gastrectomy between 2001 and 2010. A further analysis was also performed after dividing patients into three groups according to histologic subtype: SRC, well-to-moderately differentiated (WMD), and poorly differentiated adenocarcinoma. SRC patients have younger age distribution and female predominance compared with other histologic subtypes. Notably, the distribution of T stage of SRC patients was distinct, located in extremes (T1: 66.2% and T4: 20%). Moreover, the prognosis of SRC in early gastric cancer and advanced gastric cancer was contrasting. In early gastric cancer, SRC demonstrated more favorable prognosis than WMD after adjusting for age, sex, and stage. In contrast, SRC in advanced gastric cancer displayed worse prognosis than WMD. As stage increased, survival outcomes of SRC continued to worsen compared with WMD. Although conferring favorable prognosis in early stage, SRC has worse prognostic impact as disease progresses. The longstanding controversy of SRC on prognosis may result from disease status at presentation, which leads to differing prognosis compared with tubular adenocarinoma.

There is a lack of agreement on which gastric cancer screening method is the most effective in the general population. The present study compared the relative performance of upper-gastrointestinal series (UGIS) and endoscopy screening for gastric cancer. A population-based study was conducted using the National Cancer Screening Program (NCSP) database. We analyzed data on 2,690,731 men and women in Korea who underwent either UGIS or endoscopy screening for gastric cancer between January 1, 2002 and December 31, 2005. Final gastric cancer diagnosis was ascertained through linkage with the Korean Central Cancer Registry. We calculated positivity rate, gastric cancer detection rate, interval cancer rate, sensitivity, specificity, and positive predictive value of UGIS and endoscopy screening. The positivity rates for UGIS and endoscopy screening were 39.7 and 42.1 per 1,000 screenings, respectively. Gastric cancer detection rates were 0.68 and 2.61 per 1,000 screenings, respectively. In total, 2,067 interval cancers occurred within 1 year of a negative UGIS screening result (rate, 1.17/1,000) and 1,083 after a negative endoscopy screening result (rate, 1.17/1,000). The sensitivity of UGIS and endoscopy screening to detect gastric cancer was 36.7 and 69.0%, respectively, and specificity was 96.1 and 96.0%. The sensitivity of endoscopy screening to detect localized gastric cancer was 65.7%, which was statistically significantly higher than that of UGIS screening. Overall, endoscopy performed better than UGIS in the NCSP for gastric cancer. Further evaluation of the impact of these screening methods should take into account the corresponding costs and reduction in mortality.

Yun S, et al. Nutr Res Pract. 2022 Apr;16(2):233-247. https://doi.org/10.4162/nrp.2022.16.2.233